Patent Application
20140273051
1. Field of the Invention
The instant invention is generally directed to an apparatus and method of chemical sensing, utilizing multiple targets having immobilized reagents or reactants in a material matrix forming discrete sensors or targets for physical and chemical reaction sensing through spectrographic analysis of the immobilized analytes with the targeted components in the sample. More specifically, the instant invention includes an apparatus for analyzing solution sample variables using a light source incident on at least two components with immobilized analytes that examines spectrographic changes at the components with the immobilized analytes to determine properties of one or more desired variables.
2. Background of the Invention
Chemical sensors and chemical sensing technology have formed a basis of scientific investigations and technological developments throughout history. Through the centuries vigorous efforts have continued to be directed toward improving sensors. Efforts to improve accuracy, speed, and reduce overall costs continue to drive the market in sensor development. In particular, sensing specific analytes in conjunction with reagents instigating a response in a solution which has applications in many fields, from medicine to waste treatment for example, has been an area of great interest. Given the wide ranging need for such sensors, improvements and adaptation of new technologies in such sensors have a potentially substantial return.
There are several ways in which concentrations of components of a solution can be sensed. In some examples, such as measurement of pH sensing via a concentration of hydronium ions can be done. The electrochemical properties of an analyte can be used to produce an electrical signal at a specially designed probe. In the in-situ situation when these types of sensors are used, such use requires frequent calibration to ensure that drifts in measurement are accounted for due principally to accumulation of deposits from the electromechanical reaction on the sensor. Further the complex design of the electrode makes it expensive and the probes need careful considerations during shipping, handling, and installation. Also, not many other analytes of interest in a typical solution respond via an electromotive force at the target electrodes. As a result, this technique cannot be applicable for sensing a number of analyte reactions, significantly limiting the usefulness of any resulting sensors based on this technology. Additionally, the electrodes do not give a reproducible electromotive force over long periods of time, again due to fouling, thus reducing the operational life of the sensor. Lack of accuracy, shorter operational life, and a requirement to correct for this fouling or drift through frequent calibration relegates this type of measurement to laboratories and hampers real world deployment without significant drawbacks to accuracy and very high operational costs for deployment. For instance some sensor packages using this technology are used to do chemical analysis in pools. The resulting sensor packages are difficult to use, require constant maintenance and are not as accurate due to the nature of the sensors/type of sensing used.
Another ubiquitous method of testing concentration of reactants/analytes in a solution is through observation of the effect that the reactant has on a reagent that is specifically designed to interact with the reactant. This system of testing can range from reagents that change their absorption properties to those that create detectable precipitates and vary in delivery method from liquids, ranging from sprays to liquids in beakers, to paper impregnated strips. Reagents that exhibit chromism, e.g. change color, can exhibit this in different ways, including for example, but certainly not limited to absorption of incident or reflected light, absorption of energy and readmission in the same spectrum, absorption of light followed by the emission of light in a different spectrum, the change in the polarization characteristics of the light or the like. However, one of the many drawbacks of such detection methods is the addition of a reagent to a sample to instigate a color changes can result in uncontrolled absorption of the reagent by the reactant making re-sampling a necessity and potentially skewing any measurements. These systems excel, therefor, in detecting one off reactions without regard for absorption or fouling of the sample with the reagent, for instance in a laboratory where mixing in test tubes is sufficient and visual detection of changes with is sufficient, this process is useful. However, in preparing large numbers of samples or where higher accuracy measurements against the sample are needed or where consistent, high repetition, real time sampling is needed, these systems simply cannot work.
Some companies have adapted the color changing sampling technique and made systems in which those reagents are automatically, in small quantities, made to come in contact with the solution with analytes on a test strip or automatically added thereto. Devices currently available include the Hanna Instruments HI 2210 and HI208-02 Benchtop pH Meters and the Sper Scientific 860031 Benchtop pH/MV Meter and the like in the realm of pH sensors. The optical changes in the chamber are measured using a variety of optical detection techniques or electrical techniques and values are displayed. The disadvantages here are these systems tend to be complex systems which require liquids to be moved around from container to container, they require reapplication of solutions and reagents need to be restocked, calibration is required each time to calibrate batches of reagents after restocking and often in between measurements, and upfront cost and operations costs are high. And like in the case of electrical probes, the system additionally suffers as described above from fouling. It is also atypical to have more than one variable measured by such a system. Additionally, these provide a slightly higher level of accuracy than the visual color change indicator tests, but still fail to achieve the accuracy needed for some applications.
One solution to provide for more quantitative purposes with a reactant/analyte mixture require placement of the solution in an optical cuvette. The cuvette is then engaged with a spectrometer. The spectrometer can be used to show changes in absorption, fluorescence, and measures more accurately the degree of the reaction being observed. The disadvantages of this system are myriad, firstly it is still fraught with human error, for instance from human handling and constant changing of reagent stock and supply, as well as higher overall system costs and maintenance and operation costs. It is also slow and requires a large amount of bench time from highly skilled professionals to operate.
Some devices have taken this technique and made single cuvette systems in which single cuvettes are introduced to reagents with a solution with analytes in a chamber. The optical changes in the chamber are measured with one a variety of detection techniques and values are displayed. However, these solutions still only provide a specific analysis on a single sample basis, limiting the search to a single reagent/reactant analysis. Additionally, these solutions still result in overly complex systems requiring liquid solutions be handled and used to “fill” multiple samples with the reagent for analysis in the sample. This then has to be repeated for each sample and, potentially, recalibrated for each new sample. This is as a direct result of one of the principal drawbacks of the liquid/liquid on strip reagent sensing system, the reagents need to be restocked and thus the cost upfront and the cost of operation are increased, not to mention the overall cost of lab technician labor time. Additionally, as the reagents will require consistent reapplication or restocking, constant calibration continues with these systems as well and is a source of error in these systems. An example of such a system is Lamotte WATERLINK SPIN analysis machine, which can process a number of analytes for a specimen. However, the processing still requires a consumable, here a disk, with the analytes.
Recent advances in material and molecular sciences have dramatically increased the pace of advances to address some of these issues, as evidenced by the instant invention. In particular, improvements in technology and reagent delivery materials and structure have provided ever-increasing improvements in accuracy and cost effectiveness of sensors. One difficulty with reagent reactions is effective immobilization of the reagent for repetitive interaction with test sample without loss of the reagent through absorption or reactions with the reactant. One new technology for effective immobilization of reagents for sustainable and repeatable sensor gathering is Sol-Gel materials technology.
Sol-Gel materials technology has developed to provide manufacturing techniques for producing a class of materials with wide ranging applications, from dense ceramics to aerogels. The method provides for, in some instances, low temperature manufacturing of matrix structures on surfaces, bulk material, or as other products and structures. The Sol-Gel technique provides high purity, homogeneity, controlled porosity, stable temperature characteristics and nanoscale structuring for generating highly sensitive and selective matrices to incorporate reagent molecules in a surface or throughout the sol-gel structure via pores. Generally, the process involves the transition of a liquid or ‘sol’, the colloidal suspension of particles, with a precursor that is then introduced to an at least one solvent into a solid ‘gel’ thereby forming intermediary polymer structures with some specialized properties. The intermediary structures, collectively referred to herein as a xerogels, are then dispersed in any number of techniques and dried to form various structures.
A typical method of manufacture is described hereafter. Although a description of a form of sol-gel production is provided herein, the example is meant to be non-limiting. Other forms and formats for creating sol-gel materials can be used without departing from the spirit of the invention with a goal of providing a porous structure with embedded, immobilized reagents. In a principal step of a typical manufacturing process of a sol-gel material, hydrolysis of the colloidal components is conducted. This is where a precursor such as Tetraethoxy silane (TEOS), Tetrametjoxy silane (TMOS), Methyltrimethoxy silane (MTMOS) or other metal alkoxides are hydrolyzed. The hydrolysis requires a catalyst typically a very small amount of water or acid or the like. Since these metal alkoxides are not immiscible in water, a solvent such as a base alcohol suitable for the metal alkoxide, for instance in the case of TEOS an ethanol, can also be used for phase transitions.
Following hydrolysis, the condensation of the material occurs where the individual precursor molecules start connecting to each other. The material then begins gelation where the system forms a viscous liquid. This is the step where the reagents will typically be added. Further cross-links on the molecular level are formed within the viscous liquid through a process called ageing. Ageing can also be accompanied by mechanical manipulation of the product. For instance, one example of forming a thin film can be, but is certainly not limited to, spin coating which is used to form a thin layer of xerogel. The xerogel is then dried such that alcohol/water in the solution is lost and all structural bond formations are completed. Post processing from a bulk material with the matrix structure and immobilized reactant can also occur to produce the sensor material. Finally, a process called densification can be used to thermally treat and collapse the open structures to form a dense ceramic.
The result of this method allows for the design of desired materials at low temperatures with matrices ideal for encapsulating or engulfing further molecules, the structure of which is converse to the extreme temperatures typically found in manufacturing complex matrices. The result is a matrix structure that acts as porous binders for reactants or reagents. By retaining the open structure and with the additional reagents added during formation, the reagents trapped or immobilized in the spaces formed by the M-O-M bonds where M can be any metal from the precursor or combination of precursors, for instance Si—O—Si bonds.
In a further effort to fix or immobilize the reagent and prevent so called leaching over time of the reagent with the reactants, it is possible to introduce modifying fixing agents in the process of preparing the reagent. For example the modifying agents can be, but are certainly not limited to, molecules that affect the bonding of the reagents such as a trialkoxysilane when the precursor is tetraoxysilane. These agents would act to modify the reagent so that it covalently bonds to the matrix. This eliminates any leaching and further immobilizes the reagent in the sensor as an end result. Similarly, one could use a reagent that allows for it to bond chemical with the matrix using a hydrogen bond or ionic bond or the like. Additional surfactants can be used, such as but not limited to cationic trumethyl ammonium bromide, anionic sodium dodecyl sulfate, and the like. In the case of the Sol-Gel matrix created by the lower temperature processes, by adding a recognition reagent element in the Sol-Gel matrix during synthesis the resulting surface can be effectively made into a longer lasting reagent delivery surface. In the process of gel forming this can be accomplished by doping or by grafting a reagent which does not interact chemically with the surroundings during the matrix formation process. This recognition or template molecule associated with the reagent is immobilized within the sol-gel matrix as it forms by engulfing the analyte or reagent template molecule. The immobilizing process relies on various molecular forces. These forces used in creating the immobilized reagent can include but are certainly not limited being based on types of adhesion forces such as Van-der-walls forces, London forces, dipole-dipole forces. The process of engulfing the template to yield functionalized Sol-Gel materials is tailored by the type of doping or grafting procedures used. The result is an immobilized reactant in a porous surface or structure. The controlled formation of the gel can result in variations within the structure of the resulting matrix, controlling variables such as porosity, matrix size, uniformity, structural dimension, and similar variables as the material is formed. One example of the process of manufacturing a Sol-Gel matrices and material can be seen in U.S. Patent Application No. 2008/0311390 to Seal, et al. The process discloses building strata on a substrate from Sol-Gel with the aforementioned gelation and hydrolysis followed by drying. This is one of several structural methodologies that can be used to form the matrix surface.
As noted above the Sol-Gel production process can result in an intermediary called xerogel in various formations that include dense films with little uniformity, uniform bulk structures, and uniform thickness, high homogeneity, thin layer structures. Any format can be used to form the matrix for the immobilization of the reactant. Thus any number of processes can be utilized to produce a sensor, however, whatever the process must also be susceptible to the additional doping of the gel with the reagent to properly immobilize the reagent as noted above. Any open matrix material that is susceptible to the immobilization of a reagent as noted will potentially function as a sensor.
In an exemplary method of forming the Sol-Gel pad or target of the instant invention a spinning process is utilized to form a thin film. The spinning process is used together with doping of reagent in the xerogel intermediary to produce the desired engulfed, immobilized reagent in a thin film matrix. These are then used in functional pads as described herein. The end result is a thin film surface trapping an immobilized analyte that reacts with a target reactant resulting in a spectrographically detectible color change. The Sol-Gel materials process is particularly useful as most reagents used are organic in nature. Such reagents are subject to photo-degradation and denaturing over time. The inert properties of Sol-Gel materials allow for encapsulation while preserving the properties of the reagent and decreasing the rate of degradation. Additionally, several of the reagents are organic dyes which are typically volatile and the low operation temperatures in manufacturing of sol-gel allow them to be infused compared to alternate techniques.
Several scientific instrument devices and some commercial and manufacturing devices have used or suggested Sol-Gel materials for chemical sensing. In one example from Oceanoptics, a sol-gel matrix material with a reagent such as bromocresol green is coated on cuvettes. The sample can now be directly placed in the cuvette and the cuvette placed in appropriate optical test equipment which is a cuvette holder coupled to light source and spectrometer, as shown on the company's website, this obviates the need to add a separate fluid reagent as the cuvette is already coated with and retains the reagent.
In a further instance, a fiber optic tester is produced whereby the process of ageing, after the addition of reagents, the matrix is coated on ends of fiber optic cables before densification. This results in a sensor that can be directly inserted in test solutions on one end and connected to optical measurement devices such as spectrometers and light sources on the other end\. Oceanoptics manufactures examples of these systems, see for example the TP-300 and RF200 probes.
However, this method of testing is limited to one off sample testing and still requires calibration to a known point before placement of the next solution in the device. This is because the devices are sensing based on the absorption of light. Therefore it is necessary for the system to understand what the path length and attenuation is from the system (cuvette holder, fiber optics, lenses etc.). In the testing process, usually a buffer of known strength is first placed in the cuvette, data on this control is then captured. This requires additional steps, materials and labor. Then the same cuvette is cleaned and the target solution is added. The new absorption values are measured. These values are used to calculate the concentrations of a target variable. This results in admission of inaccuracies and potential errors as well as requiring the admission of the control solution for calibration between each test.
To date, no one has been able to provide cost effective and efficient sensing of multiple reactants using spectrometry in a cost effective device. One that does not require consistent recalibration and can self-detect fouling and other abnormalities. Therefore, a need exists for an apparatus utilizing multiple immobilized reagents for optical sensing of reactant concentrations that is both more cost effective, requires less maintenance, requires less recalibration, allows for auto-calibration to a reference and is more accurate than existing sensor mechanisms. Such a system would provide for a higher degree of consistency, greater resolution, lower maintenance costs, and lower manufacturing costs over existing sensor systems.
An aspect of the invention includes provision for immobilized reagents in a Sol-Gel matrix for controlled retention of one or more reagents in communication with at least one target sample.
A further aspect of the invention is provision for a more cost effective multivariate mechanism for testing samples against local reasons immobilized conversions.
Yet another aspect of the invention is automation of sample testing without the need to restock or refill agents.
Another aspect of the invention is the sensing of a targeted variable with an at least one immobilized reactant and elimination of a requirement for manual calibration at every single test point.
A still further aspect is the provision of an at least one clear, non-doped sol gel pad or blank which allows the system to automatically relate the change in the system over time through to the sensor that has the doping.
Yet another aspect of the invention is multiple sensors deployed in an in-situ flow based system.
An aspect of the invention is the use of a single light source set with independent controls for each source in the set.
Yet another aspect of the invention is the use of a single light source and single sensor using the technique of indexing the pad.
The invention includes an article of manufacture, an apparatus, a method for making the article, and a method for using the article.
The apparatus of the invention includes an apparatus sensing at least two reactants or analytes in a sample, having an at least one light source emitting energy and an at least two detection targets having an immobilized reagent within the target surface. An at least one detector, wherein the at least two detection targets having immobilized reagent thereon are in communication with the sample and the immobilized reagent interacts with the sample and energy incident on the target from the at least one light source such that the energy is changed by the interaction of the reagent and reactant and the change is in turn detected by the at least one detector and associated with a measurement of the level of the reactant or analyte in the sample.
The at least one target surface can be a matrix formed by the sol-gel technique. The apparatus may have a blank target or a target without immobilized reactant for calibration of the sensors using the at least one light source emitting energy. The at least one light source can be two or more light sources.
The emitted energy can be in at least one of the visible light, ultra violet, or infrared spectrums. The at least one light source can be a single light source. The at least one detector can be a single detector. The at least one detector can also be two or more detectors. The at least one light source can be a single light source and the at least one detector can be a single detector and the at least two targets are indexed and moved to interact with the energy emitted by the single light source and detected by the single detector.
The at least two targets can be indexed in a rotary indexer with a rotary indexing support. The at least two targets can be indexed in a linear indexer with a linear indexing support. The at least one light source can be a broad band light source emitting over multiple frequencies, wavelengths, or frequencies and wavelengths. The at least one light source can be a narrow band light source emitting small bands of energy at a specific frequency, wavelength, or frequency and wavelength. The at least one light source can be two or more light sources having a narrow band.
The apparatus may further include a controller. The controller can interrogate data from the at least one detector, analyze the data and correlates the data to a desired variable level.
The apparatus can include an at least one sample vessel. The sample can be a single sample. The single sample can contained within multiple vessel sections in the at least one vessel. The single sample can be contained in a single vessel section. The vessel can be transparent or semi-transparent to the energy emitted by the at least one light source.
The energy can be passed through the targets and can be detected by the at least one detectors on a side opposite the at least one light source. An at least one wall of the vessel can reflect the energy emitted by the at least one light source. The at least one light source can be on one side of the vessel and the energy can be emitted and isolated within a light tube portion of the vessel and is incident on a reflective surface, which is then reflected from said at least one wall through the at least two targets to the at least one detector. The energy emitted by the at least one light source can be collected by the detectors directly from the at least two targets within the solution.
The at least one detector can be an at least one spectrophotometer and a photodetector The detector can be at least one of a CMOS, CCD, Photodiode, Photoresistor, Phototransistor, and a Phototube. The at least one detector can further comprise an at least one filter. The filter can be at least one of an at least one absorptive or dichroic filter. The at least one filter includes a combination of filters reacting to specific wavelength bands to filter and detect color sensing.
The matrix can be formed using a metal alkoxide or a metal alkyloxide precursor compound. The reagent can be immobilized by at least one of Van-der-Walls force, London Forces, dipole-dipole forces, and dispersion forces within the target. The reagents can be an at least one of an organic dye, an inorganic dye, bromocresol green, cresol red, bromothymol blue, bromopyrogallol red, phenol red, orthotolidine, N—N, diphenyl-p-phenylenediamine, and melamine. The reagents can be an at least one of an at least one enzyme, Aequorin, Chloramine, and Glucose Oxidase. The reagent can activate when near an at least one of hydronium, chlorine, calcium, iron, sodium, lead bromine, magnesium, and copper. The reagents can measure at least one of oxygen, carbon-dioxide, cyanuric acid, chlorine, and glucose concentrations. The reagents can be at least one of flora and fauna. The flora can be algae or bacteria. The immobilized reagent can chemically bond to the matrix by a bond such as covalent bond, hydrogen bond or ionic bond.
The apparatus of the invention further includes a sensing apparatus having an at least one light source emitting energy with an at least one detection target having an immobilized reagent within the target surface and an at least one detection target having no reagent. An at least one detector can be provided, wherein the at least one detection target having immobilized reactants and the at least one detection target having no reagent are in communication with the sample and the immobilized reagent interacts with the sample and energy incident from the at least one light source can be changed by the interaction and the change can be in turn detected by the at least one detector and associated with a measurement of the level of the reactant or analyte in the sample and calibrated against a reference energy profile received by the at least one detector from the at least one target having no reagent.
The at least one target surface can further include a matrix formed by the sol-gel technique. The emitted energy can be in at least one of the visible light, ultra violet, or infrared spectrums. The at least one light source can be a single light source and the at least one detector can be a single detector and the at least one target with the immobilized reagent can be indexed and moved to interact with the energy emitted by the single light source and detected by the single detector. The at least one target with immobilized reagent and the at least one target with no reagent can be indexed in a rotary indexer with a rotary indexing support.
The apparatus can further include a controller. The controller can interrogates data from the at least one detector, analyzes the data and correlates the data to a desired variable level. The sample can be a single sample. The single sample can be contained within multiple vessel sections in the at least one vessel. The reagents can be an at least one of an organic dye, an inorganic dye, bromocresol green, cresol red, bromothymol blue, bromopyrogallol red, phenol red, orthotolidine, N—N, diphenyl-p-phenylenediamine, and melamine. The reagents can be an at least one of an at least one enzyme, Aequorin, Chloramine, and Glucose Oxidase. The reagent can activate when near an at least one of hydronium, chlorine, calcium, iron, sodium, lead bromine, magnesium, and copper. The reagents can measure at least one of oxygen, carbon-dioxide, cyanuric acid, chlorine, and glucose concentrations. The reagents can be at least one of flora and fauna. The flora can be algae or bacteria.
The method of the invention includes a method of sensing, having the steps of: placing a sample in a vessel in contact with an at least two detection targets having an immobilized reagents thereon; directing an at least one light source incident upon the at least two detection targets having immobilized reagents thereon; emitting energy from the at least one light source incident upon the at least two detection targets having immobilized reagents thereon such that the energy changes with any interaction the immobilized reagents have with the sample; detecting a change in the energy incident upon the at least two detection targets having immobilized reagents caused by the interaction of the immobilized reagents with the sample; and reporting the results of the detection step.
The article of manufacture of the invention includes an apparatus sensing a change in an optical profile from an at least one detection target having an immobilized reagent within at least one surface of the detection target prepared by the process steps of forming a sol-gel matrix adding a reagent into the matrix and immobilizing the reagent within the matrix; forming an at least one surface with an at least one detection target having the immobilized reagent on the at least one surface; placing the at least one detection target having the immobilized reagent on the at least one surface in a sample vessel; placing an at least one detection target having no reagent in the sample vessel; and calibrating at least one detection target having the immobilized reagent using data detected from the at least one detection target having no reagent.
The matrix can be a thin film. The thin film can be formed by spin coating or dip coating process. The matrix can be a bulk target. The article may be further prepared with the step of adding a reagent during manufacture. The sol-gel material can be prepared via sol-gel processing involving the generation of colloidal suspensions which are subsequently converted to viscous gels and then to solid materials. The porosity of the matrix is controlled during the sol-gel processing via control of at least one of a pH, a temperature and addition of selective surfactants during conversion to viscous gels and then solid materials. The surfactants can be at least one of cationic trumethyl ammonium bromide or anionic sodium dodecyl sulfate.
Moreover, the above objects and advantages of the invention are illustrative, and not exhaustive, of those which can be achieved by the invention. Thus, these and other objects and advantages of the invention will be apparent from the description herein, both as embodied herein and as modified in view of any variations which will be apparent to those skilled in the art.
Embodiments of the invention are explained in greater detail by way of the drawings, where the same reference numerals refer to the same features.
A chemical or physical reaction occurs between a reactant in concentration in the sample, something indicating a desired property of the sample that is to be measured. Reagents can include, but are certainly not limited to organic or inorganic dyes such as but not limited to, bromocresol green, cresol red, bromothymol blue, bromopyrogallol red, phenol red, orthotolidine, N—N, diphenyl-p-phenylenediamine, melamine or enzymes such as, but certainly not limited to Aequorin, Chloramine, Glucose Oxidase and the like, used alone or in any functional combination. The reagent-reactant activity measures for a variable. Variables can be for example, but certainly are certainly not limited to, dissolved analytes that can be ions such as hydronium, chlorine, calcium, iron, sodium, lead bromine, magnesium, copper, and the like; or dissolved analytes that can be compounds such as oxygen, carbon-dioxide, cyanuric acid, chlorine, glucose and the like; or flora and fauna such as algae, bacteria, and the like, alone or together in any functional combination. This occurs without the loss or absorption of the immobilized analytes in the matrices of each of the targets 130, 160. The targets are suspended on or within a further support member 210 which isolates the targets 130,160. As noted above, the exemplary embodiment employs a Sol-Gel process to provide a matrix with immobilized reagents that interact with target reactants to instigate a detectable change in an energy emission as measured by a detector.
Again, Sol-Gel is a method for forming a lattice structure which can be, but is certainly not limited to, Silicon Dioxide (SiO2) or titanium dioxide (TiO2) thin films deposited by the Sol-Gel technique. As noted surface structures and solids with the immobilized reagents throughout are also considered as are other Sol-Gel structures that immobilize reagents that can then be admitted to and interact with the sample, thereby acting as a sensor.
In an exemplary embodiment, the Sol-Gel process starts from titanium oxy-acetyl acetonate precursor or tetraethyl oxysiliane with solvents added thereto to eventually form a titanium dioxide or silicon dioxide thin film. The Sol-Gel components are combined to form into the intermediary xerogel, the analyte molecule is inserted, and the result is an engulfed analyte bound in the matrix. The xerogel is dispersed into a thin layer form and dried to form the final target pad surface. Some non-limiting examples of process for dispersing the xerogel include spinning, vapor deposition, dipping and the like. The xerogel, as a non-limiting example, is typically built on a substrate, such as that suggested in U.S. Patent Application 2008/0311390 to Seal, et al.
However, other examples of Sol-Gel have included fiber optic structures and bulk material structures can be formed and either exposed surfaces can be used or the bulk material may be sectioning to appropriate sensor targets with matrix structures immobilizing reagents as noted above. The matrix effectively immobilizes the reagent in the structure and renders the surface of the pad reactive to particularized reactants of interest for identifying physical variables of the solution, such as pH, temperature, salinity, free chlorine, and other variables as noted herein. The interaction becomes evident through spectrographic analysis as explained herein, typically through an absorption process or a fluorescing process, identified by the at least one detector 180,190. The at least one detector can be, but is certainly not limited to an at least one spectrophotometer and a photodetector. Non-limiting examples of a photodetector include an at least one of a CMOS chips, CCD chips, photodiodes, photoresistors, phototransistors, phototubes and the like.
In this instance, exemplary embodiment of
The sample 100 that is to be measured is suspended in an optically clear sample vessel 200. The sample vessel 200 with the sample 100 is shown as being unhindered, however, it is well within the spirit of the invention to provide sectioning of the sample 100 within the sample vessel 200 and/or provide sectioning of the at least one light source 110, 120 and the at least one detector 180, 190 and the combinations and exemplary embodiments shown herein are simply non-limiting examples of the types of structure embraced by the instant invention. In addition, the sample 100 though stationary in
Thus, in the exemplary embodiment of
In the exemplary embodiment of
In addition to the at least two targets 130, 160 a blank 103, either a Sol-Gel target without an immobilized reagent or a blank space or material, can be incorporated to be used for calibration purposes, as further shown in
In the exemplary embodiment shown, the measurement is completed for the first of the at least two immobilized reagent targets 130, 160 and either through user input or sensor measurement, moves the movement member 235 and thereby indexes the targets in the tray, herein the second of the at least two targets 160 is moved into position above the detector 180. The indexing, being linear, can also occur in the opposite direction so long as the subject target of the at least two immobilized analyte targets is synchronized with the at least one light source 110 and the at least one detector 180.
When an interaction of an immobilized reagent within the at least two targets 130, 160 and a reactant in solution occurs, a change in a portion of the curve 450 will occur exhibiting a change in the curve. One non-limiting example of such a change would be an absorption phenomenon, which would result in a marked reduction in the intensity of certain wavelengths of light being received at the at least one detector 180,190. Similarly, other phenomenon can increase the intensity of some wavelengths or simultaneously decrease intensity at one wavelength and increase the intensity at another wavelength. For instance, instead of simple absorption, a fluorescence phenomenon can be noted. As noted, these can occur in any number of wavelength ranges for the given at least one light source. In the exemplary embodiment shown, this would result in an optical reaction that is detectable by the at least one detector 180, 190 and reportable as a change that indicates to the detection of a desired reactant and thereby correlates to a relative scale of a desired variable or characteristic of the sample 100. This may be further enhanced as noted above by the use of filters on the light to during the course of its travels from source to detector using the filter to amply or depress specific wavelengths or regions of the profile 450.
The light sources emit light that is incident on an at least one target 610, 611 having an immobilized reagent that reacts with reactants in the sample as an indicator of properties of the sample. This interaction is measured as a change in the spectrographic absorption at the at least one target 610, 611 and this change is detected by an at least one sensor 606-608. Similarly, a calibration or reference window 615 is provided with a target that is clear or has no doping of an immobilized reagent or is otherwise non-reactive with the reactant 615 which likewise receives energy from the at least one light source 621-626 but does not have an interaction occurring that changes the energy. The reference window 615 acts as a calibration target and passes the known light profile emanating from the at least one light source 621-626. Variations in this profile indicate calibration issues which may result from conditions in the sample, for instance but not limited to turbidity, conditions in the at least one light source, for instance but not limited to light source degradation or malfunction, or when compared to other sensor results may be able to provide identification of sensor malfunctions. The at least one target component 610, 611, 615 can be removed from the system and replaced or changed to suit the environment and use of the sensor system.
Though multiple light sources are provided, a single light source may also be provided. In this exemplary embodiment, the multiple light sources 621-626 are individually addressable sources that are driven by the light source driver 620 in communication with the controller 600. The individual lights 621-626 in this case can provide light of specific narrow bands of wavelengths based on instructions from the light driver 620. The use of narrow or broad band light sources is fully contemplated and these can be used in conjunction with one another, alone or in any myriad of combinations, to provide the requisite incident energy for spectrometric analysis of the resulting light incident on the analyte and reactant interaction. These will in turn create a profile of intensity over a wavelength band, as seen in previous
In addition the controller 600 is in communication with at least one temperature sensor, thermistor, thermopile, infrared sensing, thermocouple and the like 640, at least one salinity sensor 634, and at least one displacement based flow sensor, differential pressure sensor, inductive flow sensor, coriolis flow sensor, ultrasonic flow sensor, calorimetric flow sensor and the like. 645. These additional sensors 634, 640 located in a vessel 105. The vessel 105 has a first wall 631 a second wall 632 the sensor arrangement has immobilized reagent targets 610, 611 contained therein.
The controller 600 is in further communication with a signal conditioning circuit 605 which feeds signals from the at least one detector 606, 607, 608 to the controller 600. The controller analyzes the variables relating to the various reagent-reactant reactions being detected by the at least one detector 606-608 and communicates the results through the communication component 603. This can be communicated to a user interface, to a user via visual observation, or off from this controller 600 via a wired or wireless connection to a further controller.
The embodiments and examples discussed herein are non-limiting examples. The invention is described in detail with respect to preferred embodiments, and it will now be apparent from the foregoing to those skilled in the art that changes and modifications can be made without departing from the invention in its broader aspects, and the invention, therefore, as defined in the claims is intended to cover all such changes and modifications as fall within the true spirit of the invention.
